Stocks set for weak open

NEW YORK (CNNMoney) -- U.S. stocks were poised for alower open Friday, with futures losing momentum after Caterpillar released disappointing earnings.

It's been a volatile morning, with stock futures whipsawing on either side of breakeven as investors weigh the latest batch of corporate earnings, along with the latest bailout plan for Greece and U.S. debt ceiling talks.

The aid package, which officials said will cover all of Greece's financing needs, involves lowering interest rates and extending the payback period on existing loans to Greece from the EU and International Monetary Fund.

Market momentum was carrying over to Friday, until Caterpillar released earnings, which knocked futures into negative territory.

"Caterpillar fell short of what Wall Street was expecting," said Derek Hoffman, chief executive of Wall Street Cheat Sheet. "They missed by three cents so people are selling the stock."

Companies: Before the bell, Caterpillar (CAT, Fortune 500)reported a profit of $107 million, a 30% increase from the second quarter of 2010. However, shares fell 7% in premarkets since the heavy equipment manufacturer fell short of Wall Street expectations.

Caterpillar Chief Executive Doug Oberhelman said in the company's earnings report that, "While we expect moderate U.S. economic growth, we believe a lack of confidence in the business climate is the major impediment to a stronger recovery and job creation."

McDonald's (MCD, Fortune 500) beat Wall Street expectations with a surge in earnings of $1.35 per share, compared to $1.13 in year-ago quarter. Analysts had expected earnings of $1.28 per share, according to a consensus from Thomson Reuters. Shares rose 2% in premarket trading.

Former Dow member Honeywell (HON, Fortune 500) beat analyst estimates with second-quarter earnings of $1.02 per share. The company reported revenue of $9.1 billion, excluding $234 million from a newly discontinued operation. Shares fell about 1% in premarket trading.

Verizon (VZ, Fortune 500) reported earnings per share of 57 cents, topping analyst estimates by 2 cents. The report marks a sharp turnaround from last year's second quarter, when the wireless giant reported a loss of 42 cents per share. Shares were slightly lower in premarket trading, after the company announced it didn't sell as many iPhones as anticipated.

The Wall Street Journal reported late Thursday that the Department of Justice is preparing subpoenas against its parent company, News Corp (NWSA, Fortune 500)., as part of a preliminary investigation into the company's phone hacking scandal.

On Thursday, Microsoft (MSFT, Fortune 500) said net income in its fiscal fourth-quarter rose 30% to $5.9 billion, or 69 cents per share. Analysts polled by Thomson Reuters had forecast earnings of 58 cents per share. Microsoft shares fell almost 1% in premarket trading.